Process of spinning cuprammonium cellulose solutions



Patented Sept. 1942 PROCESS SPINNING CUPRAMLIONIUM CELLULOSE SOLUTIONS Franz Hoelkeskam-p and liwald Knehe, Wuppertal-Barmen, Germany Property Custodian vested in the Alien No Drawing. Application January 18, 1940,

Serial 1939 4 Claims.

This invention relates to improvements in methods for producing artificial silk by the cuprammonium stretch-spinning process.

No. 314,562. In Germany January 18,

(oi s-5o .It is an object of the invention to provide a method for producing filaments, fibres, threads and the llkefrom cuprammonium cellulose solutions, using .the so-called stretch-spinning process and whichv is immune from drawbacks created by variations in. the amount of spinning water used and by fluctuations in the temperature at which the spinning of the filaments is effected.

' It is a further object of the invention to provide a method whereby cuprammonium artificial silk can be obtained which will possess a uniform hand, and uniform dye afiinity despite variations in the manufacturing factors recited above.

To this end the invention is based on the use of means for causing the freshly spun filaments,

threads and the like to adsorbnegative ionsof.

alkali metal silicates, such adsorption being suitable for producing filaments and threads of uniform hand and uniform dye afiinity despite the above recited variations in the manufacturing conditions.

In the manufacture of fibres and threads, such as those made of artificial silk, staple fibres, and

the like, from cuprammonium cellulose solutions by the stretch-spinning method,- the uniformity of the products obtained depends to a great extent upon the uniformity with which the threads are hardened in the spinning funnel and the latter factor in turn upon the accurate measurement of the quantity of water used in the spinning process as well as the accurate maintenance of the spinning temperature at' which'operations ucts are subsequently worked up into finished goods as 'well as unevenness when the spun or subsequently woven products are dyed. Thus, a drop in the spin water temperature imparts a harder hand to the goods and consequently leads to the production of an irregular mesh when the material is worked up. I

' The present invention makes it possible to render the spinning process immune from these drawbacks, that is, from the deleterious results accruing from the practically unavoidable variations in the amount of spinning water and the been found that the addition to the spinning water of small quantities of water-soluble an alkali metal silicate produces anastonishing eflect in this direction. Both the hand (that lathe degree of softness) as well as the dyeing capacity become most exceptionally and uniformly regulated through adoption of this measure notwithstanding variations in spinning water quantity and temperature.

Among. the substanceswhich are adapted to produce the results desired, apreferred one is ordinary sodium silicate which is preferably used in the form of waterglass. By way of describing the practice of the invention, therefore, an executional example is given herewith, it being understood that the use of waterglass is merely illustrative and that other alkali metal silicates may be used: I

A comparison control sample of skein silk of 120 denier strength was produced on an ordinary production machine for cuprammonium cellulose solutions using a quantity of spinning water amounting to 725 c. e. per minute, at a temperature of 35 C., but without rising any addition of waterglass; the material was then finished up in the usual manner.

By way of comparison, a skein silk of 120 denier strength'was produced in the same spinning machine from the same cellulose solution and using the same quantity of spinning water with the exception that 20o mg. per liter of an alkali metal silicate, such as sodium waterglass were added. The product was then worked up in an analogous manner.

as regards the products obtained, it was found that those produced with the aid of the waterglass addition were in every possible manner far more uniform than those produced .without the use of waterglass in the spinning water. This fact was readily established withthe aid of suitcould be classified in a narrowly defined range of fluctuations in the spinning temperature. It has values; In other words they were substantially uniform in quality. The products spun without the use of. waterglass however exhibited ap-' preciable variations and erratic measurement values when evaluated as to softness, so that numerous strands thereof were found to be relatively hard in some parts and again quite soft in others.

It was found that if the two products made in example given above, are worked up, say into stocking lengths, the strands that were produced with the aid of a waterglass produced a uniform mesh structure, whereas the analogous stocking 4 strands ma'de from-skeins produced without the accordance with the executional and comparison 4 use of a waterglass exhibited very appreciable detectable variations in the mesh structure. A dyeing capacity test also served very. clearly to bring out the advantage of adding a waterglass to thespinning water.

The advantageous eifects secured by adding a waterglass was also very clearly perceivable if, for example, while using the same quantity of spinning water (725 c. 0. per minute) different spinning water temperatures were deliberately used, say, temperatures of 35, 28, 24, and 21,

tion agents in the total spinning water involved. The same is'true concerning variations in the quantity of spinning water that has to be reckoned with. Under certain circumstances and conditions. quantities as small as 30 or 50 mg. per liter of addition agents may render satisfactory service, whereas in other cases 100, 200 and even 500 mg. per liter may be required.

and if 200mg. of sodium waterglass were added -to the spinning water. In the instances where a perature decreased; furtherm0re,they exhibited an unsatisfactory mesh formation and uneven dyeing capacity. Heretofore it had been impossible for many practical purposes in manufacturing a given woven article to use a plurality of artificial silk batches produced under spinning conditions where such varying prevailed. g

The quantities of the substances embracedby the present invention and that are to be added depends upon various factors and may vary within wide limits. The layout of the spinning room, and the ventilation and air conditionin'g thereof all tend to increase or decrease the danger of producing fluctuations in the temperature of the spinning water in the various individual spinning funnels, and these factors will govern the advisability of including larger or smaller quantities of the additemperatures had What is claimed is: 1. In the method of producing filaments, fibres,

I threads and the like having a uniform hand and dye afilnity from cuprammonium cellulose spinning solutions by the stretch-spinning process.

the step which comprises spinning a cuprammonium cellulose solution into water containin about -500 milligrams per liter of an alkali metaPsiIicate, said water having a temperature of about 2135 C.

2 In the method of producing-filaments, fibres. threads and the like having a uniform hand and dye amnity from cuprammonium cellulose spinning solutions by the stretch-spinning process, the step which comprises spinning a cuprammonium cellulose solution into water containing about 30-500 milligrams per liter of sodium silicate,'said water having a temperature of about 21 C.

'3. In the method of producing filaments, fibres, threads and the like having a uniform hand and dye amnity from cuprammonium cellulose spin ning solutions by the stretch-spinning process,

the step which comprises spinning a cuprammonium cellulose solution into water containing about 200 milligrams per liter of an alkali metal silicate. said water having a temperature of about 35 C.

'4. In the method of producing filaments, fibres,

threads and the like having a uniform hand and dye aiilnity from cuprammonium cellulose spin- 

